The present invention relates to sash windows and in particular to a mounting for the spring counterbalance arrangement used in such sash windows.
Modern sash window arrangements utilise flat coiled ribbon springs which are arranged to unwind as the sash window is slid and moved within a window frame. The coiled springs provide a counterbalancing force to counterbalance the weight of the sash window thereby making movement, and opening of the window easier. Typically the coiled springs are mounted, via a mounting arrangement, within a vertical channel section of the window frame or jamb. A free end, referred to as a tail, of the spring is connected to a sash shoe slidably mounted within the channel section of the window frame. The sash shoe in turn is connected to the sash window, usually towards the lower portion of the sash window.
The coil springs are generally of a constant tension type in which the outer profile of the coil itself is rotatably held and supported within the mounting, whilst an inner end of the spring is free such that the coil spring can rotate as the spring is unwound and the tail (outer end) is extended. To provide sufficient force to counterbalance the weight of the sash window multiple springs may be provided with the free ends or tails connected together.
An example of a prior arrangement, as generally described above, for mounting multiple springs for use in a sash window is described in U.S. Pat. No. 5,365,638 the contents of which are incorporated herein by reference.
As described in this prior patent, individual mounting means are provided for each of the coil springs. To provide a multiple spring assembly a number of individual mounting means are provided and stacked into an assembly within the window jamb. Other similar examples are disclosed in GB 2278626 and GB 2295634. A yet further arrangement is also described in our co-pending application GB 0027397.9 filed on Nov. 9, 2000, the text of which is incorporated in its entirety herein by reference.
In such prior systems the spring mounting assemblies are located within channels within the window frame or jamb. During assembly the spring mountings are inserted through an enlarged access portion of the channel, or inserted into the end of the channel, and are slid within the window jamb channel to the required position along the length of the channel. The mountings are then secured in position, along and within the channel, by means of a mounting screw, or number of mounting screws, which pass through the spring mounting and engage the window jamb. In this way the spring mounting, and so springs, are fixed and secured within the channel against movement within the channel.
Whilst this mounting arrangement, and similar prior arrangements, provide a practical method of mounting and supporting the springs, there are a number of problems with such an arrangement and the mounting arrangement can be improved generally.
In particular in a production environment the fitting of individual fixing screws to secure the support mounting within the channel is a relatively intricate and time consuming (and so costly) operation with the support having to be carefully aligned in position to allow the screws to be fitted. In addition the individual screws in themselves also increase the cost of the assembly. Furthermore in use and/or during assembly the sash shoe is sometimes inadvertently released from the sash window. This removal of load from the sash shoe can result in the sash shoe rapidly, and with some force, freely sliding within the channel under the tension of the counterbalance springs. The sash shoe will then contact and impact the fixed screw mounted spring support mounting with some considerable force and in some cases can fracture the support or shoe or strip the screws from the window frame. Such damage is clearly undesirable and indeed in some prior arrangements a rubber bump stop is provided to absorb the energy of any impact of the shoe with the spring support mounting. The cost of the rubber bump stop however is undesirable and also such systems do not entirely alleviate the problem.
It is therefore desirable to provide an improved sash window spring tensioning mounting arrangement which addresses some or all the above described problems and/or which offers improvements generally.
According to the present invention there is provided a sash window counterbalance spring mounting arrangement as described in the accompanying claims.
A sash window counterbalance arrangement for counterbalancing the weight of a sash window, in an embodiment of one aspect of the invention, comprises a sash window jamb with a channel defined within said sash window jamb. The channel has and is defined by a rear wall and a pair of side walls. The arrangement further comprises a sash window shoe slidable in said channel, spring means connected at one end to said sash shoe, and a spring mounting support fitted within said channel to support said spring means. In use a spring force is generated between said spring support and sash shoe to counterbalance the weight of said sash window. The spring mounting comprises at least one mounting peg which projects from said mounting to engage a mounting aperture defined within one of said channel walls to locate and secure said spring support mounting relative to said channel. Said mounting peg and aperture are arranged such that the spring support mounting is secured and located against slidable movement in use in a first direction due to the spring force, whilst movement of the mounting in an opposite direction causes disengagement of the mounting peg from the aperture.
Preferably a distal end of the mounting peg is profiled such that movement of said mounting in said opposite direction urges said mounting to disengage said mounting peg from said aperture. The distil end of the mounting peg may have a sloped profile. In particular a first portion of the distil end of the mounting peg projects further than a second portion of the mounting peg.
Furthermore a flange lip may project from a distil end of said mounting peg to define a hook means adapted to hook over a portion of the rear channel wall in the region of the aperture.
The mounting peg is preferably biassed into engagement with the aperture. Said biassing can be provided by resilient bending of the support and/or of the channel walls. Specifically said channel may further comprise front wall portions spaced a distance D from said rear wall. A front portion of said support abuts said front channel wall portions. The mounting pegs project from said support towards said rear wall such that the distance from said front portion of the support to the distil end of the mounting peg is greater than the distance D between said front and rear channel walls. In such an arrangement the support, and/or of the channel walls, are caused to deflect, or at least portions thereof, such that a resilient biassing force urging the mounting peg into the aperture is generated. The front portion of the support may comprise wing elements which project from a surface of said support, or a front surface of the support.
The support can be modular comprising a plurality of interengaged support elements. A plurality of mounting pegs may be used and provided.
A sash window counterbalance arrangement for counterbalancing the weight of a sash window, in an embodiment of another aspect of the invention comprises a sash window counterbalance arrangement for counterbalancing the weight of a sash window comprising a sash window jamb with a channel defined within said sash window jamb. The channel defined by and having a rear wall and a pair of side walls with at the extremities of said side walls inwardly directed front wall portions. A spring mounting support is fitted within said channel. The spring mounting comprises at least one mounting peg which projects from said mounting to engage a mounting aperture defined within one of said channel walls to locate and secure said spring support mounting relative to said channel. The mounting peg is resiliently biassed into engagement with said aperture.
A sash window counterbalance arrangement for counterbalancing the weight of a sash window, in an embodiment of further disclosed aspect comprises a sash window jamb with a channel defined within said sash window jamb and having a rear wall and a pair of side walls. A sash window shoe is slidable in said channel. A spring means is connected at one end to said sash shoe, and a spring mounting support fitted within said channel to support said spring means is arranged such that in use a spring force is generated between said spring support and sash shoe to counterbalance the weight of said sash window. The spring mounting comprises at least one mounting peg which projects from said mounting to engage a mounting aperture defined within one of said channel walls to locate and secure said spring support mounting relative to said channel. A distal end of said mounting peg includes a flange lip which projects from a distal end of said mounting peg to define a hook means adapted to hook over a portion of the rear channel wall in a region adjacent the periphery of the aperture defined in said rear channel wall.